1. Field of the Invention
The present invention relates to a printer with a cutter, which can appropriately cut a recording sheet drawn out of a paper roll after printing is performed on the recording sheet.
2. Description of the Related Art
At present, there are provided various kinds of many thermal printers, in which printing is performed by pressing a thermal head against a special recording sheet (heat-sensitive sheet) which changes in color when heat is applied thereto, and by developing color on the recording sheet by heating. In particular, smooth characters and multicolor graphics can be printed without using toner, ink, and the like, and hence the thermal printers are preferably used for printing of various kinds of labels, receipts, and tickets.
As represented by the thermal printers as described above, there are known many printers with a cutter including a cutter mechanism for automatically cutting the printed recording sheet. Generally, the cutter mechanism includes a fixed blade and a movable blade capable of sliding with respect to the fixed blade. Further, when the recording sheet is cut, the movable blade is slid so as to climb onto an upper surface of the fixed blade. With this, the recording sheet can be cut while being sandwiched between cutting edges of the both blades as the recording sheet is cut with a pair of scissors.
Further, as a structure in which the cutter mechanism is incorporated into the thermal printer, there are known an integrated type structure in which a cutter unit including the fixed blade and the movable blade integrated with each other is incorporated to a main body unit, and a clamshell type structure in which a detachable unit is detachably provided to the main body unit, and the fixed blade is incorporated into one of the main body unit and the detachable unit and the movable blade is incorporated into the other one of the main body unit and the detachable unit, and thus the fixed blade and the movable blade can be separated from each other.
As described in JP 2002-144655 A, for example, there is known a clamshell thermal printer including a main body unit having a movable blade, and a detachable unit having a fixed blade, in which both the main body unit and the detachable unit can turn in a direction orthogonal to a sliding direction of the movable blade, and the main body unit moves to a cutting position while pressurizing the detachable unit when the main body unit turns.
Incidentally, in each of the above-mentioned thermal printers, there may arise a problem that the movable blade is stopped during sliding due to such phenomena that foreign matters are caught between the fixed blade and the movable blade, that the recording sheet drawn out of the paper roll is caught (so-called paper jam), that blades bite each other in a process of cutting operation, and that malfunction occurs.
In this case, in the above-mentioned integrated type structure of the cutter mechanism, it is necessary that a releasing knob or the like for manually sliding the movable blade be provided, and that the movable blade be forcibly retreated through manipulating this knob to thereby be restored to a state before the problem arises. Therefore, restoring work for the movable blade is complicated, and there is a problem that a burden is imposed on a user.
Meanwhile, in the above-mentioned clamshell type structure as described in JP 2002-144655 A, when the movable blade is stopped halfway, the movable blade covers the fixed blade from an upper surface side of the fixed blade. Thus, if the main body unit and the detachable unit are intended to be turned, there is a problem that the detachable unit cannot be released due to contact of the fixed blade with the movable blade. Therefore, in order to release the detachable unit, it is necessary that the movable blade be retreated manually in the same manner as that in the case of the integrated type structure.
Further, when the recording sheet is cut, it is necessary that the movable blade be slid while the fixed blade is held in press-contact with the movable blade at a moderate contact pressure. In this case, in the clamshell type structure, in order to perform stable printing and cutting operation, it is necessary to reliably fix the main body unit and the detachable unit to each other while positioning between the main body unit and the detachable unit is performed.